I just wanted to confirm that it is a BB data plan that you have. Many times, members think they have one and really do not. Thanks for confirming it.

I am thinking that OS 4.5 takes more memory that the original OS 4.2 that it shipped with. Plus it only has 64 MB of memory. That might be at least part of the problem. A battery pull will usually clear out the old stuff and you have done that also.